`flux build kustomization` fails on Windows

[alexanderlinne]

Describe the bug

flux build kustomization fails on Windows when using a --path other than .. On Linux, all invocations with ., a relative path or an absolute path for --path succeed and correctly render the manifests.

Steps to reproduce

1. Create a local folder test with a kustomization.yaml

   kind: Kustomization
   
   resources:
   - test.yaml
   

2. Create test.yaml in the test folder with some test manifest like:

   kind: Pod
   metadata:
     name: test-pod
     namespace: default
   spec:
     containers:
     - name: test-container
       image: nginx:latest
   

3. Create a test.yaml with:

   kind: Kustomization
   metadata:
     name: test
     namespace: default
   

4. cd into the test folder on Windows and run flux build kustomization test --namespace default --kustomization-file ..\test.yaml --path . --dry-run
5. The commands succeeds and prints the pod manifest
6. cd .. and then flux build kustomization test --namespace default --kustomization-file .\test.yaml --path .\test\ --dry-run
7. Observe the error ✗ failed to generate kustomization.yaml: failed to save original kustomization.yaml: open test\test\kustomization.yaml.original: The system cannot find the path specified. <nil> <nil>
8. Run flux build kustomization test --namespace default --kustomization-file C:\<absolute-path>\test.yaml --path C:\<absolute-path>\test\ --dry-run
9. Observe the error ✗ failed to generate kustomization.yaml: failed to save original kustomization.yaml: open C:\<absolute-path>\test\C:\<absolute-path>\test\kustomization.yaml.original: The filename, directory name, or volume label syntax is incorrect. <nil> <nil>

Expected behavior

All invocations with ., a relative path or an absolute path return the rendered manifest

Screenshots and recordings

No response

OS / Distro

Windows 11

Flux version

v2.7.5

Flux check

N/A

Git provider

No response

Container Registry provider

No response

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct